*Groan* So much for following the directions! They said "Fill in any gaps. To make a proper sculpt map, you must have no holes in the UV map." So I filled in the "gaps" at the top and bottom. Took quite a while to do well, too! I'm planning on putting this on a mega-prim, so the hole probably would end up being visible at the much-larger size that allows, I was thinking.
Here are the two versions of my UV maps (remember that I don't have the original file, unfortunately, and can't seem to revert either one):
"COMMITTED SUBDIVISIONS"
"REMAPPED"